/**
 * Created with Intellij IDEA.
 * Description:
 * User: 33013
 * Date: 2023-10-19
 * Time: 22:27
 */
import java.util.*;
public class Test {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        int n = in.nextInt();
        if(n <= 1){
            System.out.println(-1);
            return;
        }
        int[][] arr = new int[n][1 + 2 * (n - 1)];
        for(int i = 0; i < n; i++){
            arr[i][0] = 1;
            arr[i][2 * i] = 1;
            for(int j = 1; j < 2 * i; j++){
                arr[i][j] = arr[i - 1][j - 1] + arr[i - 1][j];
                if(j - 2 >= 0){
                    arr[i][j] += arr[i - 1][j - 2];
                }
                if(i == n - 1 && arr[i][j] % 2 == 0){
                    System.out.println(j + 1);
                    return;
                }
            }
        }
        System.out.println(-1);
    }
}
